Carbon-based nanocarriers for plant growth promotion: Fuelling when it needs

Climate change (i.e., rising temperature and precipitation) due to global warming is affecting soil fertility, thereby significantly causing a decrease in agriculture production worldwide. At the same time, increasing demands for food supplies with the growing global population puts extra pressure to improve agriculture production. Indeed, chemical fertilizers and pesticides are a great help in fuelling agro-production, but their excess use could deteriorate the environment and human health. Nevertheless, nanomaterials especially carbon-based nanostructured materials (CB-NMs) have revolutionized the agriculture sector in various ways including the on-demand supply of essential nutrients, biomolecules, and growth factors to plants. Carbon nanofibers (CNFs) are one such example that can be tuned to carry essential nutrients (i.e., Fe, Cu, Zn, Mo) and deliver to plants when and what is in need. As a result, it not only improves the crop yield but also maintains the nutritional quality (protein, carbohydrate, and mineral contents) of plant products. This review discusses the most innovative development in CB-NMs-based carriers (CNFs, carbon nanotubes (CNTs), and graphene as well as its derivatives) for plant growth applications including the approaches being used for their lab-scale synthesis. In addition, their application as the carrier of micronutrients and biomolecules showcasing the successful delivery (and underlying mechanism) of genes, nucleic acids, microbes, and their component in plants are discussed.